Cutter-bar actuating mechanism



OC- 30, 1951 P. E. SCHARF 2,573,068

CUTTER BAR ACTUATING MECHANISM Filed April 2l, 1949 /n Ve/Qfo/f. Pefct/ /mef'chorf.

Patented Oct. 30, 1951 UNITED STATES PATENT QFFICE Percy Elmer Scharf, La Riviere, Manitoba, Canada Application April 21, 1949, Serial N0. 88,766

1 Claim. l

My invention relates to new and useful improvements in cutter-bar actuating mechanisms,

an object of my invention being to provide a device of the character herewithin described whereby the cutter-bar is maintained under tension at all times thereby preventing distortion or buckling thereof.

A further object of my invention is to provide a device of the character herewithin described which in view of the foregoing object is particularly adaptable for use with substantially wide span cutter-bars. t

Another object of my invention is to provide a device of the character herewithin described Which is adaptable for use with machines such as swathers, combines, reapers and the like using a reciprocating cutter-bar.

A still further object of my invention is to provide a device of the character herewithin described which incorporates means whereby the pitmans may be adjusted readily as to length thereby facilitating the setting of the actuating mechanism.

A yet further object of my invention is to provide a device of the character herewithin described which is economical in manufacture, simple in construction, and otherwise well suited for the purpose for which it is designed.

With the foregoing objects in view, and such other objects and advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, my invention consists essentially in the arrangement and construction of parts all as hereinafter more particularly described, reference being had l to the accompanying drawings in which:

Figure 1 is a fragmentary side elevation of the cutting table of a swather with my device in situ.

Figure 2 is a top plan view of my assembly with the supporting framework removed for clarity.

Figure 3 is a top plan fragmentary view of an alternative embodiment of my device particularly suitable for use with mowers having a cantilever cutter bar.

In the drawings like characters of reference indicate corresponding parts in the different figures.

Considerable diiculty is experienced in the operation and maintenance of agricultural machinery such as swathers, combines and the like which incorporate a relatively wide reciprocating cutting bar in that the conventional method of drive incorporates a push-pull action to the blade. Due to the flexibility of the blade considerable whip or distortion occurs during the push or thrust stroke of the action thereby causing severe binding with subsequent heavy wear to the cutter element.

The present invention relates to an actuating mechanism whereby the cutter-bar is always under tension thereby enabling a relatively wide spanned bar to be used with the minimum of frictional interference and subsequent improved eiciency.

Proceeding therefore to describe my invention in detail it will be seen upon reference to the accompanying drawings that I have illustrated the cutting assembly of a conventional swather I which includes the supporting framework 2 comprising the rear vertical members 3 and the forward vertical members 4.

A conventional cutter-bar 5 spans the scoop portion 6 adjacent the stationary cutting teeth 'I in the conventional manner. A pair of sprocket Wheels 9 are freely journalled for rotation upon the forwardly inclined stub axles III supported within brackets II attached to the members 4 of the supporting framework 2 in conjunction with l U bolts II which embrace the stub axles I0 and extend through the brackets to be bolted thereto.

f These sprocket wheels are mounted outboard of the ends I2 of the cutter-bar 5 as clearly shown in Figure 2 of the accompanying drawings.

A pair of single-lay sprocket chains I3 extend around the aforementioned sprocket wheels 9 one end of each chain being anchored to each end I2 i having the aforementioned fork ends I5 screwthreadably engageable with the lower ends thereof and upper fork end portions I9 also screwthreadably engaged within the opposite ends. In this connection it should be noted that the upper and lower fork ends I 9 and I5 respectively are oppositely threaded in order to provide lengthwise adjustment to the pitmans I 'I. A wrench-engaging portion 20 is provided along the length of the barrel I8 the rotation of which either extends or withdraws the aforementioned fork ends I5 and I9 thus lengthening or shortening the effective length of the pitmans so that the aforementioned chains I3 can be kept at the correct tension.

The upper fork ends I9 of the pitmans I1 are pivotally connected to eccentric assemblies 2I situated upon each end of a rotatable drive shaft 22 carried within pillow bearings 23 secured to 3 the vertical members 3 of the supporting framework 2 by bolts 23 engaging bed-plates 23A extending from said vertical members. Shaft 22 is rotated by means of a sprocket and gear assembly 23 driven by the source of power (not illustrated) of the implement.

The aforementioned eccentric assemblies 2| comprise an offset crank 24 carrying a crank pin 25 adjacent the extremity thereof to which is connected the aforementioned fork ends I9 of the pitmans and in order to maintain the cutterbar 5 under tension at a-ll times it should be noted that the points of attachment of the eccentric assemblies 2| to the rotatable drive shaft 22 are diametrically opposite as clearly shown in Figure 2 of the accompanying drawings.

In operation, the effective length of the pitmans I7 is adjusted as hereinbefore described in order to eliminate any backlash in the chains |3 whereupon conventional lock-nuts 26 are u tightened thereby securing the fork ends l5 and |9 to the barrel portion I8. Rotation of shaft 22 will cause the crank arms 24 to revolve and due to the diametric opposition thereof will cause the cutter-bar 5 to be reciprocated or oscillated from side to side remaining under tension at all times.

Figure 3 of the accompanying drawings shows an alternative embodiment of my device particularly suitable for use with mowers, having a cantilever cutter assembly. Under these conditions it will be appreciated that considerations of structure make the aforementioned assembly impracticable and therefore I have provided a cutter-bar actuating assembly collectively designated 21 comprising in combination with a cutter-bar 28 carried within the extending member 29, a freely journalled sprocket wheel 30 mounted for rotation upon a spindle 38' secured to and extending upwardly from member 29 near the outboard end 3| of bar 28.

A single lay sprocket chain 32 extends around the wheel 3U and is connected to the end 3| of the bar 28, the opposite end of chain 32 being secured to one end of an adjustable length pitman 33. This pitman is mounted at the rear of the member 29 and parallel to the cutter bar 28 being capable of endwise movement within the bearings 34 secured to member 29. Length adjustment of this pitman is provided by a barrel 33 internally screw-threaded at the ends thereof with left and right threads respectively. The adjacent ends 33" of the pitman are correspondingly threaded and engage the ends of said barrel, locking nuts 33A being provided in a conventional manner.

A rotatable drive shaft 35 actuated by a source of power (not illustrated) is mounted within a pair of bearing standards 36 attached to the 4 framework 31 by bolts 36 substantially at right angles to the cutter bar 28 and the pitman 33 and at the inboard end 38 thereof.

A double crank eccentric assembly 39 is provided on the lower end of drive shaft 35 in the form of a crankshaft having a pair of diametrically opposite cranks 40 and 40. Crank 40 is connected to one end of the pitman 33 by means of sprocket chain 4I and crank 40' to the inboard end 38 of the cutter bar 28 by means of sprocket chain 4|.

In operation, rotation of shaft 35 causes cranks 40 and 40 to reciprocate the pitman 33 and the cutter bar 28 from alternate ends thus maintaining the bar 28 under tension at all times.

Since various modifications can be made in my invention as hereinabove described, and many apparently widely different embodiments of same made within the spirit and scope of the claim without departing from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

What I claim as my invention is:

A cutter-bar actuating mechanism comprising in combination with said bar and a supporting framework, a freely journalled sprocket wheel mounted on said framework near one end of said cutter-bar, a single-lay sprocket chain extending around said wheel and being anchored at one end to one end of said cutter-bar, an adjustable-length pitman secured to the opposite end of said chain capable of endwise movement substantially parallel to said cutter-bar, a rotatable drive-shaft connected to a source of power, and a double-crank eccentric assembly at one end of said shaft, a flexible connection between one of said cranks and the adjacent end of said shaft, and a further flexible connection between the other of said cranks and the other end of said cutter-bar to effect oscillating movement of said cutter-bar, said flexible connections ensuring tension in said cutter-bar during operation thereof.

PERCY ELMER SCHARF.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date y668,877 Holdshoe Feb. 26, 1901 796,268 Toeger Aug. 1, 1905 1,200,983 Quesnell Oct. 10, 1916 1,652,125 Greer Dec. 6, 1927 2,109,436 Schomengerdt Feb. 22, 1938 2,484,861 Stewart Oct. 18, 1949 

